Hovering airplane



A. F. ZAHM.

HOVERING AIRPLANE.

APPLICATION FILED JAN. 22, 1919.

1,401,934, Patented Dec. 27, 1921;

2 SHEETSSHEET I.

54 al wenroz ALBERT F. ZAH M.

A. F. ZAHM. HOVERING AIRPLANE. APPLICATION FILED MN; 22, WW.

Patented Dec. 27, 1921.

ALBERT E ZAHM.

his 6H I g C L I nmrs n starts RQTENT 'QFFECE.

ALBEB'I'I. ZL-HH, WASHINGTON, DISllBIO'l' OF conmm.

aovsnmc mrnann I spehifleation of Letters Patent Patented Dec. 2'7,1921.

Application Med January 22, 1919'. Serial R0. 272,558.

To all whom c'tmay concem:

Be it known that I, ALBERT F.' ZAEM, a

citizen of the United States, residing at rect vertical lift frompropellers operating deflection of the propeller ainblast in anapopposite sides of the longitudinalaxis of in a true horizontal plane,as in a helicopter, such lift is derived through the reaction of the air(deflected frdm its course as defined by the propellers) upon a wingsection especially adapted to that purpose-the pro pellers meanwhilerotating about substantially horizontal axes or in an approximatevertical plane. This downward reaction of the air may be secured inseveral ways. The leading edge of the airplane wings, for instance, maybe pivoted and the wings in consequence given-a very large angle ofincidence, or, if desired, the wings may be given a flexible or pivotaltrailing edge por tion and heavily cambered. The result in each instanceis identical, i. 6., the propelling force realized from the propeller orpropellers is converted into vertical lift by the proximate downwarddirection through its reaction onthe biased or deeply-cambered wings. 1u

Another characteristic of the invention is the mounting of the airplanewings in superposed relation and one aft or slightly to the rear of theother as they progress rearwing. This arrangement increases or enhancesthe aero-dynamical efliciency of the by eliminating the blanketingtendency apparent when the wings are forwardly staggered or directlysuperposed with the result that there is no interference whatsoeverbetween the superposed "wings.

The". wings (referring to the opposed groups rather than the individualwing) at the craft are independently movable and may be shiftedsufliciently to laterally balance the machine by increasing ordecreasing the lift on either side. The use of ailerons is thus avoided.Moreover, as a result of such adjustment the angle of incidence of thewings can be lessened to three degrees positive or even less and liftobtained by reaction of air thereon in the usual manner;

the machine under such. circumstances operated as an airplane of theconvention made to climb vertically or nearly so, the

thrust efi'ont realized from the. propellers being suflicient to securethe required lift. As a military craft i-t posesses both the advantagesof a helicopter and the advantages of an-airplane, although helicopters,

up to this time have been impractical due to. a lack of horse power perunit of weight. To hover or remain stationary while in mid-air it is butnecessary that the motor be throttled down until the force of gravityand the lift force are equilibrated and the wings manipulated until theangle thereof satisfies the above conditions. Hoveringaction is possiblein either of its positions of flight for the reason that the lift forceis sufiicient, whether flown as an airplane (keelhorizontal) or as ahelioo ter, to counter-act the gravitational force. ngitudinal trim,while climbing verticallyor at a steep angle, with thev fore and aftaxial line of the selage horizontal, is through manipulation of the rearcontrols, 2'. e., the elevator flaps; as it is proposed to position therear control surfaces that the wardly and upwardly from the lowermostslip stream or air-blastffrom the propellers acts or rather reactsdirectly upon them regardless of the position or attitude of the"machine. 7 The structural advantages derived as a result of the relativearrangement of the airplane parts and in consequence of its . Myinvention in the novel features and combinations of parts hereindescribed by way of exarnple inv their preferred em bodiments, andtheinvention is more particularly pointed out in the appended: cla ms.Further objects and advantages of-the invention will more fully appearfrom the following description taken with the accompanying drawings.

Of the drawings, wherein like characters of reference designate like orcorresponding Figure 1 is a side elevation. of the imlproved machine'illust ted diagrammatica y. r r

Fig. 2 is a front end elevation.

Fig. 3 is a plan view. 7

Fig. 4 is a diagrammatic perspective view showing the wing control.

Fig. 5 is an enlarged cross sectional view of one of the wings(flattened out).

Fig. 6 is a similar view, the position of the trailing edge ortion ofthe wing, when biased, being indicated in dotted lines, andv Fig. 7 is'a further cross sectional view illustrating a modified form of'wing. The.fuselageor body'of the craft, designated as 10 is streamlinedthroughout and at its tail end is equipped with an empennage of more orless conventional form. The

empennage consists ofa vertical fin 11, main rudder 12,'auxiliary rudder13, main horizontal stabilizer "14, auxiliary horizontal stabilizer 15,main elevator flap 16 and auxiliary elevator flap 17 the stabilizersurfaces 14 and 15 being negatively staggered and superposed. The mainrudder 12 is mounted in direct rearward continuation of the form(normally) thewings,

. centrally propellers driven by a sing e stabilizer fin 11 and theauxiliary stabilizers 15 respectivelyfat opposite sides thereof.

The location of the auxiliary rudders is such that the rudderscollectively .(also ele-- vator flaps) operate in the direct path of thepropellerflslip tral,prop.eller.

N earer' the forward .end of .the' fuselage than the rear end a numberofsuperposed supporting surfaces or wings are mounted. These wings,

stream as defined by the cengress upwardly from the lowermost wing.lthough of a given profile or cross sectional collectively may be warpedor biased to an extent deemed suflicient to deflect the air-blast fromthe propellers vertically or nearly vertically downward .whereby an uward force isexerted upon the wings. he propellers of which there arepreferably three are, ar-.

ranged symmetrically at opposite sides of the fore and aft axis of themachine end thereof, the field of the several being substantially equal(see Fig. 2) to the total area of theiwing'strueture as measured fromtop to bottom and tip to tip. In other words, the arrangement. of thepropellers is such that the total supporting surface area lies in theslip stream thereof. r r

The several ropellers are preferably power. unit designated as inconnection designated respectively 18, .19, '20, 21 and 22 aresuperposed and located one slightly aft of the otheras they pro- 23inclosed, for the major part, in the forward end of the'fuselage 10. Thecentral propeller 24 is directly driven by the power that the air-blastof the side propellers is relied upon for the derivation of the verticallift to a greater extent than the central propeller 24. Accordingly theside propellers are mounted in closer proximity to the leadin% edges ofthe several wings.

y negatively staggering the supporting surfaces or wings a blanketing ofthe air is eliminated and each giving made to exert a maximum of lift.The wings, or rather the supporting surfaces (see diagrammatic view,Fig. 4) preferably consist of separate panels, to wit; a central panel(only the 'centen'panel of the lower wing as herein illustrated). andopposed outer panels. The outer panels of each wing or supportingsurface are provided with flexible trailing edge portions 26while thetrailing edge portions of the central panel or panels are fixed. Thewings throughout are founded upon wing beams 27 and 28 of suitabledesign.' Therear wing beams of the several wings carry the trailing edgeportions 26 to which they are pivotally secured as at 29. In the flightof the machine as an airplane the trailing edge portions of the severalwings extend rearwardly in substantially streamline prolongation of themain body of the wings or in lateral continuation of the fixed trailingedge portions of the central panels. When it :is desired that the thrustvalue of the outer propellers or rather v biased or moved to the angularpositions in,-

dicated by dotted lines in Fig. 1 with a result that the air streamreacting upon them is deflected downwardly. This deflection of theair-blast of the propellers converts the thrust or at least the greaterportion of the izhfrust into direct or substantially vertical Tomaintain the equilibrium of the ma chine fore and aft while operatingunder the conditions above outlined the. rear control surfaces arepositioned as indicated, z. e., directly to the wing structurecharacterized" by an absence of adjustable or movable wings. The 'midsection of the wing structure justable obviously the air-blast from thepropellers is unaffected whereby the rear. controls are renderedeflective as controlling agents under all conditions other words,

being non-adof flight. In by subjecting the rear controls 1 III rear ofthat portion of the to the full air-blast of the center propeller at alltimes their operativeness is assured.

The mechanism for flexing or controlling the angularity of theadjustable wing sections comprises separate control levers 30 and 31conveniently inclosed within the fusela e, in close proximity to thepilots seat. ach lever is directly connected by a rod 32 and lever 33with a shaft 34 inclosed in one of the wings of the particular groupwhich the individual levers 30 and 31 control. The shafts 34 arepreferably inclosed in the supportin surfaces 21, one in'each wingthereof an extended throughout the greater portion of their length. Atintervals throughout the length of each shaft rearwardly extending arms35 are provided. These arms are rigid with the shafts and connect withtrailing edge strips 36 inclosed in the wings 21 at or near theirtrailing edges. Accordingly in operation the levers 30 and 31 are moved,the shafts 31 turned, the arms 35 swung downwardly, and the wingsproportionately biased (see Fig. 6) for simultaneously fiexin all of thewings of the opposed groups. 'fiae several trailing edge sectlons ofeach group are interconnected as indicated at 37 in Fig. 4. The rigidconnection between the superposed wings may be efiected by wing posts 38and wiring 39 in the ordinary manner.

In order that the vertical field of the propellers 25 may lie in avertical plane slightly aheadof the wing structure a special form ofengine bed mountin is provided. Inverted triangulated \fisupports 38'are erected upon the lower supporting surface 22 at or near the ends ofthe wing structure. These supports constitute an adequate mounting forthe transmission (not shown). To decrease the head resistance in flightas a true airplane the transmission mechanism is inclosed in streamlinecasings 40 at the forward ends of which the propellers 25 are dis osed.

he landing gear 41 may be of any well known character although it ispreferred that the struts be streamlined as a. unit and arranged todiverge downwardly from the fuselage slightly ahead of the center ofgravity of the machine. Preferably the center of gravity of the machineis located slightly to the rear of the resultant center of lift wherebyin climbing vertically on an .even keel the elevator flaps are given apositive angle to exert sufiicient lift to properly elevate the tail.

In the modification illustrated in. Fig. 7 the wing 4-2 is deeplycambered and made variable by pivoting it as at 43. The wing,

V is supported by struts 44 and controlled by any suitable means. Theinterconnection between the wings indicated at 45 is for.

the same pu ose as the intersection indicated at 37 in ig. 4. By heavilycambering ned by the propeller with the result that direct or nearlyvertical lift; is obtained rather than forward thrust, the thrust beingneutralized by the drift.

A machine of this character may be launched from and landed upon thedeck of a ship as well as from the roof of a building. It may belaunched straight into the air in a confined space so that the value ofthe machine from a'milita point of view as well as from a commercialaspect is increased. If desired, when once in the air the nose end ofthe machine may be tilted up by manipulation of the rear controls andthe machine flown as a helicopter, sufiicient lift being derived fromthe separate propellers to obtain this end. The power plant should ofcourse be sufficiently light per unit of horse power to make the machinea practical success and as the. development of such aeronautical motorspossessing the above characteristics has already taken place the machineis entirely practical in every respect. I In lieu of ailerons formaintaining lateral equilibrium of the machine the opposed groups ofwings are operated to mcrease the lift value on .that side of themachine tilted down. Other mechanism may of course be. installed.- Thearrangement of the supporting surfaces one above and to the rear of theother prevents the deflected air from the upper from coming down uponthe top surface of the next wing beneath blanket the air. The degree ofnegative stagger however is immaterial since it is only necessary toremove the superposed wings lon 'tudinally to a slight extent.

While have described my invention in detail in its present preferredembodiment,

it will be obvious to those skilled in the art after understanding myinvention, that various changes and modifications may be made thereinwithout departing from the spirit or scope thereof. I aim in t eappended claims to cover all such modifications and changes.

What is'claimed is:

a 1. In an airplane, the combination, of a plural number of propellers,the axes of the propellers being horizontal, curved supportlng surfacesincluding ad'ustable and fixed wing panels, the adjustable win panelsbeing movabl into peller air-blast 1s deflected downwardly with theresult that suficient vertical lift obtained to bodily lift the machineinto the air without altering its flying attitude and without alteringthe angular relation of the propeller axis to the horizontal, togetherwith a control surface for maintairng the sitions where y the prolit 'ing machine in longitudinal trim, the location of the control surfacerelatively to the fixed panel being such that the propeller win airlastsuccesslvely imp' the fixed wing panel and the control surface under allflight conditions.

2. In an airplane, the combination, of a ropeller, a curved win designedto deflect ownwardly the propel er air-blast, the degree of deflectionbeing such that thethrust value of. the propeller operating in asubstantially vertical plane is converted into approximate verticallift, a second propeller, a comparativel flat wing section arrangeddirectly behind said second propeller, and a control surface so arrangedrelatively to the flat wing section and to'the second propeller that theair-blast from the propeller acts successively upon the flat wingsection and the control surface under all conditions of flight. V 3. nairplane including in combination,

a superposed tier of negative staggered supporting surfaces, at leastone of the supporting surfaces comprising a rigid wing section and anon-rigid wing section, the non-rigid wing section of each wing beingsufliciently elongated transversely of the ma- ;hine to extendsubstantially throughout the plural number of vertically rotating-propellers so arranged relatively to the supporting surfaces that themajor portion of the area of the total number of the surfaces lie in thepropeller slip stream, means for rotating'the propellers, and means foradjusttlie angular relation of the non-rigid wing section to deflect theair blast of the cggopeller in a substantially vertically downrddirection.

4. In an airplane, a supporting surface comprising a relatively smallrigid and relatively large non-rigid win sections, a propeller arrangedto direct its air-blast over the rigid section of the wing, a pluralityof propellers arranged to direct their air-blast over the non-rigidsection of the wing, and means for biasing the non-rigid wing section todeflect the air-blast of the second length of the supporting surface,a.-

closed in the fuselage, a propeller, a wing structure including acomparatively sma substantially ver- 1 rigid and comparatively largenon-rigid wing sections, the rigid wing-section being so related to thepropeller that the air-blast thereof bathes its surface,'-directionalcontrol surfaces located to the'rear of the rigid wing section, saidsurfaces being also bathed by th air-blast of the propeller under allconditions of flight and additional propellers arranged out laterallfrom the fuselage at opposite sides thereofithe arrangement of said lastmentioned propellers being'such that the non-rigid wing sections followin the slip stream, thereof.

6. In an airplane, thecombination, of a plurality of negativelystaggered superposed supporting surfaces, one of said supportin surfacescomprising a relatively small xed center panel and comparatively largedivided outer panels, the line of divisio-n between the sectionsconstituting said outer panels being extended longitudinally of the wingstructure, means for deflecting the trailing sections of the outerpanels downwardly, a central propeller, a directional control surface,the relative arrangement of the central propeller and the directionalcontrol surface being such that the slip stream of the propellerimpinges successively the center panel and the directional controlsurface under all flight conditions, side propellers, the relativearrangement of the side propellers to the outer wing panels being suchthat the propeller slip stream impinges successively the forward sectionand the adjustabl trailing section of said outer panel, means to biasthe trailing sections ofsaid outer panels downwardly to such 'an extentas to direct the propeller sli stream substantially vertically downwarALBERT FJZAHM.

